The present invention relates to a disk playback device that uses a turntable to support and rotate a disk. More specifically, the invention relates to a device that determines various destination positions of an internal disk transporter by measuring incremental relative displacement of the disk from a reference position.
Disk players with internal transport mechanisms, for ejecting at disk and moving the disk to various positions within the player, are known. When the disk is transported to a playback position, an imperfect alignment between the disk and the playback position can render playback impossible. For example, in players that employ a turntable with a spindle that moves toward the disk to fit insert the spindle into the center hole, the spindle cannot be inserted into a misaligned disk. In devices that employ a tray to support and carry the disk, a misalignment can sometimes be corrected by moving the disk out of the playback position and returning it, causing the disk to settle into its tray. However, in devices in which the disk transporting mechanism has no disk-supporting tray, for example one that supports the disk by its edge using moving belts or rollers, moving the disk is ineffective. In such devices, the disk is frictionally engaged by its edge. Thus, the disk position does not change relative to the surface that engages it, so misalignment cannot be corrected by moving the disk back and forth. If an alignment problem develops, the disk must be ejected.